1. Technical Field
Methods and apparatuses consistent with the present invention relate to measuring a state of a plurality of channels and selecting an idle channel.
2. Description of the Related Art
A cognitive radio technology determines a current state of a channel according to a region and time, and based on the determination, selects an appropriate frequency, modulation, and an output, so as to communicate, dynamically moving an idle channel in real time. A technology related to such cognitive radio technology has been actively developed so as to use limited frequency sources.
In order to induct such technology, which efficiently uses the idle channel, into an ultra high frequency (UHF) band, a technology capable of rapidly detecting a primary user (e.g. a sky wave channel) that has a priority of use of a channel, and capable of communicating between devices which are not the primary user, by using the idle channel that is a channel not used by the primary user, becomes an important technology.
FIG. 1 is a diagram illustrating a conventional method of scanning a channel state.
In operation 110, a base station transmits to a terminal a channel state scanning request for scanning the channel state.
In operation 120, the terminal transmits to the base station a request received response indicating that the terminal has received the channel state scanning request.
At this time, if the base station does not receive the request received response, the base station again transmits the channel state scanning request to the terminal.
In operation 130, the terminal reports to the base station the channel state scanned according to the channel state scanning request.
In operation 140, the base station transmits to the terminal a report received response indicating that the base station has received the channel state report from the terminal.
At this time, if the terminal does not receive the report received response, the terminal again reports the channel state to the base station.
Here, the base station receives the report including information regarding communication quality of the channel, and whether the channel is in use.
However, the conventional method has problems in that the conventional method does not provide a specific method of measuring communication quality of a plurality of channels, and when the base station and the terminal select an idle channel from among a plurality of idle channels so as to perform communication, the conventional method does not consider a location of a terminal, an application, or the like.